Telephone system.



F. W. WOOD.

TELEPHONE SYSTEM.

nruouron nun JULY 6, 1906.

Patented Mar. 9, 1909.

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UNTTED TATES *rnr FFTQE.

FRANK W. WOOD, OF NEWPORT NEWS, VIRGINIA, ASSIGNOR TO CHARLES CORY ANDJOHN M. CORY, OF NEW YORK, N. Y.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented March 9, 1909.

To all whom it may concern:

Be it known that I, FRANK W. WOOD, a citizen of the United States,residing at Newport News, in the county of Vilarwick and State ofVirginia, have invented new and useful Improvements in TelephoneSystems, of which the following is a specification.

This invention relates to telephone systems and its object is to improvesystems of the character described as can be best set forth inconnection with the accompanying drawings of which Figure 1 is a diagramof the connections and apparatus of sufiicient of a telephone system toillustrate the application of the invention, and Fig. 2 is a simplifieddiagram showing the relative connections of stations in talkingcommunication.

Referring to the drawings, the system comprises a plurality of telephonesets A, 13 etc., each comprising a transmitter, receiver, signal andappurtenant apparatus and connections as will be hereinafter referredto, and a central switchboard with apparatus for efiecting desiredconnections and promoting communication between the stations includingan operators set C, line drops D, D etc., clearing-out drops E, E etc,talking batteries F, F etc, a ringing generator G or ringing battery H,means as push buttons I, I etc., for closing the ringing circuits, anauxiliary central signal K as will be hereinafter referred to, keyswitches L, L etc, M, M etc, N, N etc, 0, etc, for effecting connectionsas hereinafter described.

The mechanical construction and arrangement of the central switchboardand apparatus is not shown or described in this application as it formsthe subject matter of a separate application and is unnecessary to anunderstanding of the invention claimed herein, the diagrammatic drawingsand description thereof for ning a part of this application beingsufficient for that purpose.

Each of the key switches is like every other and therefore a descriptionof one will apply to each. The key switch N, for instance com rises 18contacts 1 to 18 inclusive. Contacts 2 and 4 are permanently connoctedtogether as are also contacts 8 and 10, and 14 and 16 respectively.Contacts 2 and S, 4 and 5, 8 and 9, 10 and 11, 14 and 15, 16 and 17 arenormally in contact in respective pairs. To operate the switch contactsa key 19 pivoted at 20 is provided. To the key is pivoted a member 21carrying bars 22 23 and 24: adapted when moved in one direction fromnormal respectively to engage with contacts 5, 11 and 17, break theirrespective contacts with contacts 4, 10 and 16 and move them intocontact respectively with contacts 6, 12 and 18, the connections thenbeing as illustrated at N. The movement of the key in the otherdirection from normal operates to remove the contacts 2, 8 and 18respectively from contact with contacts 3, 9 and 15 and bring them intoconnection with contacts 1, 7 and 13 respectively as illustrated byswitch L. The normal position is illustrated by switch M. The device foractuating the contacts is suitably insulated to prevent the formation ofa circuit through it.

It will be observed that the key switches are arranged in sets ofparallel rows at right angles to each other as rows containing L, M etc,and L, M etc., are parallel as are also rows containing L, L etc., andM, M etc, but the row containing L, L etc., and parallel rows are atright angles to the row containing L, M etc. and parallel rows. Tofacilitate the description, one set of rows may be considered verticaland the other horizontal. Let it be considered that the row containingL, L etc., and parallel rows are vertical. The apparatus and connectionsof each of the horizontal rows are the same as every other one andtherefore a description of one will apply to each of the others. Takingthe top row (L, M etc.,) as an instance therefore, a conductor 25connects together contact 6 and all the corresponding contacts of theother switches of the row and connects them with the contact 7 and thecorresponding contacts of the other switches in the row. A conductor 26connects contact 12 and analogous contacts of the other switches of therow together and to contact 1 and analogous contacts of the otherswitches of the row. The talking battery F has one terminal connectedwith one terminal of the clearing-out drop E and the free terminals areconnected, one with a conductor 27 which is also connected with thecontact 18 and the corresponding contacts of the row and the other witha conductor 28 which is also connected with contact 13 and thecorresponding contacts in the row.

To a switch, as N, of each vertical row is connected a telephone set asB, a conductor 29 connecting contact 17 with the junction of thetransmitter 30 and receiver 31, a conductor 32 connecting contact 11with a contact controlled by the receiver hook and a conductor 33connecting the contact 5 with another contact controlled by thereceiver. In the diagram, for the sake of clearness, two hooks areapparently shown. It will be understood, however, that there is but onehook and that the illustration is intended to show that there are two searate connections controlled by the hook. ne of the connections, whenthe hook is down, connecting conductor 32 with one terminal of the bell34 and the other connection connecting conduc tor 32 with the otherterminal of the bell. When the hook has risen, conductors 32 and 33 arerespectively connected with receiver 31 and transmitter 30. In a similarmanner set A is connected with switch 0. To one of the switches of oneof the vertical rows is connected the operators set C. Thus conductor 35connects contact 17 with the junction of the receiver 36 and transmitter37, conductor 38 connects contact 11 with a terminal of the receiver andconductor 39 connects contact 5 with a terminal of the transmitter.

Contact 15 of switch N is connected by conductor 40 with contact 17 ofswitch N, contact 9 is connected by conductor 41 with contact 11 andcontact 3 is connected by conductor 42 with contact 5. In a similarmanner switch N is connected with switch N so that all the switches inthe vertical row are connected as indicated and in a similar manner theswitches of each vertical row are connected.

The operation of the apparatus and the circuits employed may be now setforth.

Suppose that a person at one telephone set as B, desires to conversewith some one at an other point as at A. The receiver is lifted from thehook at B when the following circuit may be traced: from battery H(assuming that the switch 43 is thrown upward) through conductor 44,contacts 2, 3", 4" and 5 of switch N, conductor 45, similar contacts ofswitch 1 conductor 42, contacts 2, 3, 4 and 5 (it being assumed that allthe switches are in normal position), conductor 33, transmitter 30,conductor 29, contacts 17, 16, 15 and 14, conductor 40, similar contactsof switch N, conductor 46, similar contacts of switch N, conductor 47,line drop D, conductor 48, relay 49, (hereinafter referred to) conductor50 to the other terminal of the battery H. The line drop which may be ofany well known self-restoring type is now energized and signals theoperator that a call has been made. Thereupon the operator actuates oneof the switches, as N, in the vertical row corresponding to the line droactuated. In this case the handle of the switc 1 is thrown down,bringing the switch into position as shown. The operator also throws theswitch,

as L, in the vertical row corresponding to the operators set and in thehorizontal row with the switch previously thrown, in the oppositedirection from that in which the switch N was moved, the switch L beingthen in the position shown. Circuits may now be traced as follows: fromthe junction of the operators receiver 36 and transmitter 37, throughthe receiver 36, conductor 33, contacts 11 10 8 and 7 conductor 25,contacts 6 and 5 of switch N, conductor 33, transmitter 30 at set B,conductor 29, contacts 17 and 18, conductor 27, clearing-out.

drop E, talking battery F, conductor 28, and contacts 13", 14 16 and 17to the junction of the receiver 36 and transmitter 37. Circuit may alsobe traced from the said junction through the transmitter 37, conductor39, contacts 5 4 2 and 1 conductor 26, contacts 11 and 12, conductor 32,re ceiver 31, conductor 29, contacts 17 and 18, conductor 27, drop E,battery F, conductor 28 and contacts 13 14 16 and 17 to the aforesaidjunction. The operators instrument and that at station E are nowconnected as shown in Fig. 2 from which it will be seen that thereceiver of one and transmitter of the other are connected in series inone branch, the remaining receiver and transmit ter are connected inanother branch and that the two said branches are connected in mul-.

tiple across a third branch containing the talking battery andclearing-out drop con nectcd in series. This arrangement is conducive toloud talking, and the clearing-out drop, which may be of a.well knowntype, is energized, thus indicating that the line is in use.Conversation can now be carried on between the station and operator andupon the latter ascertaining what station is wanted as, for instance, A,the ringing button I corresponding to station A is pushed therebyclosing a circuit as follows: from one terminal of battery H throughconductor 50, button I, conductor 51, contacts 8(), 99, 10O and 11"0,conductor 52, similar contacts of switch 0, conductor 53, similarcontacts of switch 0, conductor 54, bell 55 (the receiver being on thehook) conductor 56, contacts 50, 40, 30 and 20, conductor 57, similarcontacts at switch 0, similar contacts at switch 0 and conductor 44 tothe other terminal of battery H. The circuit being thus completedthrough the bell 55, it will ring and attract the attention of a personat station A, who will respond in the usual manner by removing thereceiver from the hook. A switch, as O, in the vertical rowcorresponding to the station and in the same horizontal row as theswitch (N) already thrown, is thrown by the operator in the oppositedirection to that in which N occupies. The operatoralso brings hisswitch (L) to normal thus disconnecting his set. Circuits may now betraced through the two connected stations A and B, similar to thosealready traced between the operators set and that at station B.Conversation may be carried on and upon its conclusion and the hangingup of the receivers, the talking circuits will be broken and indicationof this fact conveyed to the operator by the restoration of theclearing-out drop which takes place automatically upon itsdenergization. Upon such a signal the operator restores the key switchesconcerned to their normal positions.

In order that the coil of the clearing-out drop E, which is in thetalking circuit, may not interfere, by its induction, with thetransmission of talking currents, means is provided for neutralizing theeiiect of the inductance of the coil. This may consist of anon-inductive resistance 60 connected across the coil of the drop,although other means of neutralizing the inductance may be employed. Thenoninductive resistance may be conveniently formed by winding a coil or"the required resistance with hah its turns reversely wound on the otherhalf. It should be of suitable ohmic resistance to shunt suiiicient ofthe steady current into the drop coil to actuate the drop but at thesame time to act as short circuit about the drop coil tor the rapidlyvarying talking currents which are greatly opposed by the inductance ofthe drop coil. By throwing the switch 43 downwardly the generator G maybe connected to the ringing circuit in place of the battery H which, ifa storage battery, may be then charged.

The relay 49 before referred to as being in the circuit with the linedrop is energized when a call is made and attracts its armature 61 and,it the switch 62 is closed, closes a circuit from the battery H throughconductor 63, bell 64 and conductor 50, thereby ringing the bell inaddition to throwing the drop. This is of service to attract theoperators attention to a call especially when the drop is obscured as atnight. The bell can be cut by opening the switch 52.

From reference to the foregoing and the drawings it will be apparentthat there is a vertical row of switches corresponding to each outstation and that there is a line dro and ringing button corresponding toeacli vertical row and its station, also a vertical row of switchescorresponding to the operators set. This reference will also makeevident that the switches 01 each vertical row are connected onedirectly with its corresponding telephone set, to this switch which isdirectly connected with the telephone set is connected another switchand with the last mentioned switch till another switch is connected andso on. In other words, the switches corresponding to a given telephoneset are connected in sertatim with the set. It will also be seen thatthere is a I battery adapted to supply current in common to connectedstations and a clearing-out drop corresponding to each horizontal row.The conductors corresponding to the horizontal row for connecting twostations are common to all the switches of the horizontal row andtherefore when conversation is being carried on between any two stationsthrough those conductors and by the use of its corresponding talkingbattery, in order to avoid interference it is necessary to employ theconductors and common battery of some other horizontal row for joiningany other two stations desiring conversation. Upon the throwing of aswitch in one of the horizontal rows to establish a connection theconnection between that switch and others below it in its vertical rowthat is, other switches not between the switch in question and thetelephone set to which it corresponds, is broken in a manner as beforeindicated and therefore subsequent throwing of another switch cannotoperate to interfere with the conversation through the connectionsalready established. it will be noted also that the circuit of the linedrop corresponding to each vertical row is completed through thecontacts of each and all the switches of its vertical row when thoseswitches are all in normal positions and therefore the throwing of anyone of the switches to establish a connection operates to deenergize thedrop which restores itself to normal position. served that the callingcircuit of each out station is completed through contacts of each andall of the switches of its vertical row when they are in normal positionand therefore the throwing of any one of the switches opens the callingcircuit to the station.

From the foregoing it will be evident that when a horizontal row isoccupied by having stations connected through two of its switches thatthe clearing-out drop corresponding to the row will be displayed. Vr hentherefore a call is received at the central station the operator byglancing at the line drops can ascertain the vertical row correspondingto the calling station and by running nis eye down along theclearing-out drops until he comes to a horizontal row which is not inuse he throws switches in that row as before indicated in connectionwith the topmost horizontal row and stations A and B with results alsoindicated.' it will now be apparent that there must be horizontal rowsof switches equal in number to the number of conversations it isdesired. to carry on simultaneously and as before observed there must bea vertical row of switches for each station. In the apparatusillustrated there are four vertical rows and three horizontal rows andtherefore this system provides for three out stations and an operatorsset It will further be oband the number of horizontal rows is suflicientto enable the carrying on of three simultaneous conversations providingsufficient out instruments and corresponding vertical rows of switchesto render this number of conversations possible are provided. It will beseen that the system might be extended indefinitely by adding stationsand vertical rows and horizontal rows.

While the invention has been illustrated in what is considered its beststructure and arrangement it may be embodied in other structures orarrangements and should not therefore be limited to the structure orarrangement shown.

What I claim is 1. In a telephone system, the combination with aplurality-of telephone sets, each comprising a receiver and atransmitter, of a clearing-out drop, a source of electrical en'- ergy,and means for connecting the receiver of one set and the transmitter ofanother in series in one branch circuit, the said source and drop inanother branch circuit and the other transmitter and receiver of thesaid sets in series in another branch circuit, the said branch circuitscontaining the receivers and transmitters being connected in multipleacross the branch containing the said source and drop. 7

2. In a telephone system, the combination with a plurality of telephonesets, each comprising a receiver and a transmitter, of a clearing-outdrop, a source of electrical energy, means for connecting the receiverof one set and the transmitter of another in se rice in one branchcircuit, the said source and drop in another branch circuit and theother transmitter and receiver of the said sets in series in anotherbranch circuit, the said branch circuits containing the receivers andtransmitters being connected in multiple across the branch containingthe said source and drop, and a non-inductive resistance connected inshunt with said drop.

3. In a telephone system, the combination with a plurality of telephonesets, each comprising a receiver and a transmitter, of a clearing-outdrop, a source of electrical en'- ergy, and means at a central point forconnecting the receiver of one set and the transmitter of another inseries in one branch circuit, the said source and drop in another branchcircuit and the other transmitter and receiver of the connected sets inseries in an other branch circuit, the said branches containing thereceivers and transmitters being connected in multiple across the branchcontaining the said source and drop.

4. In a telephone system, the combination with a plurality of telephonesets, each comprising a receiver and a transmitter, of a clearing-outdrop, a source of electrical energy, means at a central point forconnecting the receiver of one set and the transmitter of another inseries in one branch circuit, the said source and drop in another branchcir cuit and the other transmitter and receiver of the connected sets inseries in another branch circuit, the said branches containing thereceivers and transmitters being connected in multiple across the branchcontaining the said source and drop, and a noninductive resistanceconnected in shunt with said drop.

5. In a telephone system, the combination with a plurality of telephonesets, each comprising a receiver and a transmitter, of a clearing-outdrop, a source of electrical energy, means for connecting the receiverof any one of said sets in series with the transmitter of any other ofsaid sets in one branch circuit, the remaining transmitter and receiverof the connected sets in another branch circuit, the said source anddrop in another branch circuit, the said branches containing thereceivers and transmitters being connected in multiple across the branchcontaining the said source and drop.

6. In a telephone system, the combination with a plurality of telephonesets each comprising a receiver and a transmitter, of a clearing-outdrop, a source of electrical energy, means at a central point forconnecting the receiver of any one of said sets in series with thetransmitter of any other of said sets in one branch circuit, theremaining transmitter and receiver of the connected sets in anotherbranch circuit, the said source and drop in another branch circuit, thesaid branches containing the receivers and transmitters being connectedin multiple across the branch containing the said source and dro 7? In atelephone system, the combination with a plurality of telephone setseach comprising a receiver and a transmitter, of a clearing-out drop, asource of electrical energy, means for connecting the receiver of anyone of said sets in series with the transmitter of any other of saidsets in one branch circuit, the remaining transmitter and receiver ofthe connected sets in another branch circuit, the said source and dropin another branch circuit, the said branches containing the receiversand transmitters being connected in multiple across the branchcontaining the said source and drop, and a noninductive resistanceconnected in shunt with said drop.

8. In a telephone system, the combination with a plurality of telephonesets, of a plurality of rows of switches, one row corresponding to eachof said sets, each of said switches being adapted to establishconversational connections for its set, the contacts of all switches inone row being normally connected in series and a line-drop correspondingto each telephone set and common to all of the said row of switchescorresponding to that set, the circuit of the line-drop being completedthrough all of the said switches corresponding to its telephone set,each of said switches being adapted to break the circuit of saidline-drop when the switch is moved from its normal position.

9. In a telephone system, the combination with a plurality of telephonesets each comprising a signal, of a plurality of switches correspondingto each set and having interconnected contacts, each of said switchesbeing adapted to establish conversational connections, of a source ofcurrent, ac-ircuit adapted to be closed through said source of current,the signal of any telephone set and all of the switches corresponding tothat set, the contacts of said switches being connected in series andeach of said switches being adapted to close said circuit when they arein normal position and to open said circuit when a switch is moved fromits normal position.

10. In a telephone system, the combination with a plurality of telephonesets having the usual receiver hooks, a switch corresponding to each ofsaid telephone sets, conductors common to said switches and adapted toconnect the same to place the said sets in communication and aclearing-out drop common to said switches, said clearing out drop beingcontrolled by the receiver hooks of said telephone sets.

11. In a telephone system, the combination with a lurality of telephonesets having the usual receiver hooks, a switch corresponding to each ofsaid telephone sets, conductors common to said switches and adapted toconnect the same to place the said sets in communication and aclearing-out drop and a source of current common to said switches, saidclearing out drop being controlled by the receiver hooks of said telephone sets.

12. In a telephone system, the combination with a plurality of telephonesets, of a plurality of switches corresponding to each set, all of saidswitches being arranged in rows, each row comprising a switchcorresponding to each of said telephone sets, a group of conductorscorresponding to each row and common to the switches thereof, the saidconductors of a row being adapted to connect any two switches of the rowto place their corresponding telephone sets in communication and asource of current corresponding to each of said rows and common to theswitches thereof.

13. In a telephone system, the combination with a plurality of telephonesets, of a plurality of switches corresponding to each set all of saidswitches being arranged in rows, each row comprising a switchcorresponding to each of said telephone sets, a group of conductorscorresponding to each row and common to the switches thereof, the saidconductors of a row being adapted to connect any two switches of the rowto place their corresponding telephone sets in communication and aclearing-out drop corresponding to each of said rows and common to theswitches thereof.

14. In a telephone system, the combination with a plurality of telephonesets, of a plurality of switches corresponding to each set all of saidswitches being arranged in rows, each row comprising a switchcorresponding to each of said telephone sets, a group of conductorscorresponding to each row and common to the switches thereof, the saidconductors of a row being adapted to connect any two switches of the rowto place their corresponding telephone sets in communication and asource of current and a clearingout drop corresponding to each of saidrows and common to the switches thereof 15. In a telephone system, thecombination with a plurality of telephone sets, of a plurality ofswitches corresponding to each of said telephone sets, said switchesbeing arranged in rows, each row containing a switch corresponding toeach of the said telephone sets, a set of conductors corresponding toeach of said rows and adapted to connect any two switches of the row toplace their corresponding telephone sets in communication, a source ofcurrent and a clearing-out drop corresponding to each of said rows andcommon to the switches therein and a line-drop for each of saidtelephone sets and common to its switches.

In testimony whereof I have hereunto set my hand in presence of twosubscribing wit- Bass 65.

FRANK W. WOOD. Witnesses J. E. WARREN, E. W. House.

